WASHINGTON — The head of the FBI contradicted Attorney General Alberto Gonzales' sworn testimony and Senate Democrats requested a perjury investigation Thursday in a fresh barrage against President Bush's embattled longtime friend and aide.

In a third blow to the Bush administration, the Senate Judiciary Committee issued subpoenas to compel the testimony of Karl Rove, Bush's chief political adviser, in connection with its investigation.

"It has become apparent that the attorney general has provided at a minimum half-truths and misleading statements," four Democrats on the Senate Judiciary Committee wrote in a letter to Solicitor General Paul Clement calling for a special counsel to investigate.

The developments marked a troubling turn for Gonzales as well as the administration, which has been on the political defensive since congressional Democrats launched an investigation seven months ago into the firings of U.S. attorneys.

That probe revealed information that Democrats have sought to weave into a pattern of improper political influence over prosecutions, of stonewalling and of deceit in sworn testimony before Congress.

The White House defiantly stuck by Gonzales and denied that FBI Director Robert S. Mueller had contradicted the attorney general. Presidential spokesman Tony Snow said Gonzales and Mueller can make only limited comments in public about the classified program.

"This is the latest in a long line of artful distortions by people who have spent the last six months hurling allegations at the attorney general," Snow said. "It is inappropriate and unfair to ask people to testify in public settings about highly classified programs."

"The president meanwhile maintains full confidence in the attorney general," he added.

Democrats insisted that Gonzales had been untruthful and that the White House had encouraged top aides to flout congressional subpoenas in the U.S. attorney probe.

But Gonzales took the toughest hits Thursday, when four Senate Democrats issued a list of examples of what they said was the attorney general lying to Congress under oath — the basis for their request to Clement to appoint a special counsel to investigate.

Among the Democrats' examples of Gonzales' untruthfulness was his emphatic and repeated statement to the Judiciary Committee Tuesday that his dramatic nighttime visit to the bedside of Attorney General John Ashcroft in 2004 was not related to an internal administration dispute about the president's secret warrantless eavesdropping program.

Last year, Gonzales told the panel that there had been no internal administration dispute about the program, but former Deputy Attorney General James Comey told the panel that he, Ashcroft and Mueller were among the top Justice Department officials who believed the program was illegal and were prepared to resign over it.

In his own sworn testimony Thursday, Mueller contradicted Gonzales, saying under questioning that the terrorist surveillance program (TSP) was the topic of the hospital room dispute between top Bush administration officials.

Mueller was not in the hospital room at the time of the dramatic March 10, 2004, confrontation between Ashcroft and presidential advisers Andy Card and Gonzales, who was then serving as White House counsel. Mueller told the House Judiciary Committee he arrived shortly after they left, and then spoke with the ailing Ashcroft.

"Did you have an understanding that the discussion was on TSP?" asked Rep. Sheila Jackson Lee, D-Texas, in a round of questioning that may have sounded to listeners like bureaucratic alphabet soup.

"I had an understanding the discussion was on a NSA program, yes," Mueller answered.

Jackson Lee sought to clarify: "We use 'TSP,' we use 'warrantless wiretapping,' so would I be comfortable in saying that those were the items that were part of the discussion?"

"The discussion was on a national NSA program that has been much discussed, yes," Mueller responded.

The NSA, or National Security Agency, runs the program that eavesdropped on terror suspects in the United States, without court approval, until last January, when the program was put under the authority of the Foreign Intelligence Surveillance Court.

Other examples of what Sen. Charles Schumer called Gonzales' "lying" that merited a probe by a special prosecutor included the attorney general's sworn testimony that he had not spoken about the firings with other witnesses because the matter was under investigation.

His former White House liaison, Monica Goodling, testified under a grant of immunity that Gonzales had privately recounted his recollections of the firings and asked for her opinion on his version.

"There's no wiggle room," Schumer said. "Those are not misleading. Those are deceiving. Those are lying."

Not signing the letter to Clement was Senate Judiciary Committee Chairman Patrick Leahy, D-Vt., who instead sent a letter to Gonzales Thursday giving him a week to resolve any inconsistencies in his testimony.

"The burden is on him to clear up the contradictions," Leahy said.

Ranking Republican Arlen Specter, R-Pa., agreed, calling the call for a special counsel premature, and he took particular aim at Schumer, who has led the probe into the firing.

"Senator Schumer's not interested in looking at the record, he's interested in throwing down the gauntlet and making a story in tomorrow's newspapers," Specter said.

Meanwhile, Leahy subpoenaed Karl Rove, the architect of Bush's rise to the White House and his top political adviser, to provide testimony and documents related to the firings by Aug. 2. Also subpoenaed is a White House political aide, J. Scott Jennings. The Justice Department included both men on e-mails about the firings and the administration's response to the congressional investigation.

White House Counsel Fred Fielding has consistently said that top presidential aides — present and past — are immune from subpoenas and has declared the documents sought off-limits under executive privilege.

On Wednesday, the House Judiciary Committee approved a contempt citation against two other Bush confidants, Chief of Staff Josh Bolten and former White House Counsel Harriet Miers. The full House is expected to vote on the citation in the fall, but the Justice Department has said it won't prosecute the two.